<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="../react18/react.development.js"></script>
    <script src="../react18/react-dom.development.js"></script>
    <script src="../react18/babel.min.js"></script>
</head>

<body>
    <div id="app"></div>
    <script type="text/babel">
        // 类式组件中加一个state属性
    class App extends React.Component{
      
        state = {
            count :0
        }
        
        render(){
            const {count} = this.state;
        return(
           <div>
            <button onClick={this.handle}>点击增加数字</button>
            <h1 style={{color:'red',fontSize:'100px'}}>{count}</h1> 
            </div>
            )
        }
    handle=()=>{
        //直接修改state，不会调用render，不会渲染
        this.state.count++;
        console.log(this);
        }
    }
        const root = ReactDOM.createRoot(document.getElementById('app'));
        root.render(<App />)
  </script>
</body>

</html>